Hydrocracked lubricants

ABSTRACT

HYDROCRACKED LUBRICATING OILS WHEN TREATED WITH AN ORGANIC PEROXIDE IN THE PRESENCE OF A SYNTHETIC HYDROCARBON LUBRICANT OR ESTER LUBRICANT OR ADDITIVE CONTAINING ABSTRACTABLE HYDROGEN ATOMS PRODUCES PRODUCTS HAVING IMPROVED VISCOSITY PROPERTIES AND OXIDATION STABILITY.

United States Patent O 3,594,320 HYDROCRACKED LUBRICANTS Bernard A. Orkin, Cherry Hill, N .J assignor to Mobil Oil Corporation No Drawing. Filed Feb. 19, 1968, Ser. No. 706,632 Int. Cl. C10m 1/18 US. Cl. 252-59 7 Claims ABSTRACT OF THE DISCLOSURE Hydrocracked lubricating oils when treated with an organic peroxide in the presence of a synthetic hydrocarbon lubricant or ester lubricant or additive containing abstractable hydrogen atoms produces products having improved viscosity properties and oxidation stability.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the treatment of hydrocracked lubricating oils and in particular, it relates to hydrocracked oils treated with organic peroxides.

Description of the prior art US. Pats. Nos. 3,128,246 and 3,206,405 describe treatment of conventionally refined mineral oils and ester lubricants with peroxides. However, hydrocracked petroleum fractions obtained from heavy distillates or still bottoms of refining operations are not the same as the fluids of these two patents. Moreover, the patents do not describe the interaction between substances of different chemical structure.

SUMMARY OF THE INVENTION It has now been discovered that hydrocracked mineral oil may have improved properties for lubricating purposes by heating the said hydrocracked oil in the presence of an organic peroxide having the structure as follows:

wherein Ar and Ar may individually be phenyl, naphthyl, diphenyl or dinaphthyl or alkyl-substituted derivatives thereof containing from 1 to 10 alkyl carbon atoms.

DESCRIPTION OF SPECIFIC EMBODIMENTS By treating the hydrocracked stock in accordance with the present invention with from to about 25% by weight of the organic peroxide, the reaction product is a viscous fluid which may be used as a lubricant base stock having an increased viscosity index.

The hydrocracked stock employed in this invention may be obtained by subjecting to known hydrocracking techniques, a charge stock boiling above the gasoline range,

- and which may include virgin heavy distillate oils or residual fractions boiling at about 650 F. or higher, cycle stock, etc. These stocks may either be asphaltic or deasphalted prior to hydrocracking. Hydrocracking procedures are not a limitation of this invention, and any conventional hydrocracked petroleum-derived products may be employed.

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The peroxides which can be used in this invention include organo-hydroperoxides and diorgano-peroxides. Preferably, the dialkyl peroxides are used having from 1 to about 10 carbon atoms, such as dimethyl peroxide, diethyl peroxide, dipropyl peroxide, di-n-butyl peroxide, ditertiary butyl peroxide, dihexyl peroxide, tertiary-butyl perbenzoate, and the like. Acyl peroxides, i.e. dibenzoyl peroxide, acetyl peroxide, etc. may also be used. The most preferred are tertiary-alkyl peroxides, especially 'butyl peroxide.

The synthetic ester fluids useful in this aspect of the invention include esters produced from polyhydric alcohols and monocarboxylic acids, or monohydric alcohols and dicarboxylic acids. The polyhydric alcohols preferably have from 2 to 4 hydroxy groups, and they contain no beta-hydrogen atom, as represented by the neopentyl configuration. Typical of the polyhydric alcohols of this type are neopentyl glycol, 2,2-diethyl-1,3-propanediol trimethylolpropane, and pentaerythritol. The carboxylic acids are preferably aliphatic acids having from 1 to about 25 carbon atoms and preferably from about 4 to about 12, including butyric, valeric, caproic, caprylic, pelargonic and the like. The most preferred of these synthetic esters are pentaerythritol esters of monocarboxylic acids having from 4 to 12 carbon atoms, including esters of mixed acids.

The synthetic hydrocarbon fluid which may be used in this aspect of the invention include olefinic fluids and polymers of olefins, having from 5 to 15 carbon atoms, including dimers, trimers, and tetramers thereof, and hydrogenated derivatives. The preferred of the hydrocarbon polymer fluids are hydrogenated trimers and tetramers of decene. Thus, these fiuids may have from about 10 to 40 carbon atoms. Paraflinic hydrocarbon fluids may also be used.

It is customary to blend a base stock with additives to enhance its performance under arduous conditions. In accordance with this invention, the additive which may be added to the base stock, prior to peroxide treatment, is an aromatic secondary amine, such as diphenylamine, dinaphthylamine, phenylnaphthylamine, ditolylamine, diethyldiphenylamine, dioctyldiphenylamine, and the like. Alkyl groups attached to the aromatic rings may have from 1 to about 12 carbon atoms. The most preferred amines in accordance with this invention incluude N- phenyl-l-naphthylamine, N-phenyl-Z-naphthylamine and dioctyldiphenylamine.

The two synthetic fluids and the aromatic secondary amine each contain abstractable hydrogen atoms. During the reaction involving the hydrocracked stock and a second component in the presence of the organic peroxide, it is believed that one or more hydrogen atoms are removed from the molecules of each of the components, and there is a resulting interlinkage either with another molecule of itself or with that of another component in the reaction mixture. Hence, a molecule of the hydrocracked stock may become bonded to the molecule of the ester or to an olefin polymer or to the amine. Alternatively, the ester may become linked with the polymer or amine. It is believed that any sub-combination of unions could occur in the reaction. Such combination is dependent only on the availability of abstractable hydrogen atoms and the concentration of the components. Thus, homopolymers may form by dehydrocondensation of a number of molecules of the same compound or the molecules of the separate components can be bonded to each other producing a fluidadditive molecule, or a fluid fluid -additive molecule, and so on. It is not known whether such molecules are so produced. However, it is clear that the resulting reaction product has improved viscosity properties evidenced by the increase in viscosity index and improved stability. The

only requirement of each of the components is that it possesses at least one abstractable hydrogen atoms.

In accordance with this invention, the hydrocracked stock is mixed with from about 1% to about 75% by weight of total composition of either the ester or the polymer hydrocarbon fluid. If the amine is used, the concentration of the amine may range from about 0.5% to about 10%, and preferably from 1% to about 5%, of

an ester of pentaerythritol and a mixture of C and C acids (B); a 50:50 mixture of hydrogenated decene-l trimer and decene-l tetramer (C); N-phenyl-l-naphthylamine (PAN); and di-tertiary butyl peroxide (DTBP). In each preparation, the hydrocracked stock and the second components are premixed, and the peroxide is added as in the detailed example. The results of the evaluations are as follows:

Ester polymer PAN. DTBP, Pour point. Example HC oil, g oil, g. oil. g. g. g. F. Sludge 14. 6 153 Trace 14. 6 137 Nil. 29. 2 155 5 Light 29. 2 141 Nil. 29. 2 153 Nil. 29. 2 141 10 Light. 20. 2 135 5 Moderate. 29. 2 153 10 Nil. 18. 0 153 10 Light. 131 Heavy.

127 65 Nil. 131 ---65 C 128 65 the reaction mixture. The peroxide is present in an amount ranging from about 1% to about by weight, preferably 2% to 15% by weight of the reaction mixture.

The reactions for producing the reaction products of this invention are carried out under generally constant conditions regardless of the components present. The components are placed in a flask at a temperature ranging from about 100 to about 200 C. The desired components are added to a reactor, and under agitation and heat, the peroxide is added slowly. When that addition is complete, heating is carried out for an extended period of time, approximately from 4 to 10 hours. The final product is stripped to remove the volatile materials, normally the alcohols produced from the deterioration of the peroxide, or water and alcohol in the case of the hydroperoxide. The remaining reaction product represents the product of this invention. It may be used alone as a base lubricant or added to another base stock as an additive.

The following examples illustrate the invention and are not deemed to be a limitation thereof. All parts and percentages unless otherwise stated are on a weight basis.

Example l.Into a flask equipped with a stirrer, a heating mantle and thermometer, are added 162 grams of a hydrocracked stock having a pour point of 20 F., a viscosity index of 131 and produced from hydrocracking a Mid-continent propane-deasphalted residium. The contents were heated to 140 to 150 C. under agitation. To the flask were added 14.6 grams of di-tertiarybutyl peroxide over a two-hour period, and the resulting mixture was heated for an additional six hours. The final product was stripped to 205 C. under 8 to 10 mm. Hg. The remaining product was filtered through diatomaceous earth filter aid. The resulting product had a viscosity index of 153.

The hydrocracked stock and its treated product were subjected to an oxidation test carried out at 425 F. Samples of each of the fluids were added to containers in which steel, copper, lead and aluminum metal samples had been placed; these metals represent metals of construction normally used in engines and which may also tend to catalyze oxidation of a lubricant. Air at the rate of 5 liters per hour was passed through. The test was conducted for a period of 24 hours. The amount of sludge was measured. The following results were obtained:

Sludge Hydrocracked stock Heavy Peroxide treated stock Trace Several reaction products are prepared and evaluated under the conditions of the aforenoted example. The following components are used in various combinations in the reactions: a hydrocracked oil (HC); an ester of pelargonic acid and a 2,2-unsymmetrical-1,3-propanediol (A);

The results from tests carried out on the above products show that the peroxide treated or hydrocondensed hydro cracked stocks alone or in the presence of other fluids or the aromatic secondary amine have substantially high viscosity index to make them available as lubricants over a Wider temperature range. Stability under oxidation conditions at high temperatures is also evidenced by the lack of any sludge formation to an great extent whereas the hydrocracked stock alone results in considerable sludge formation under the same conditions.

A composition made according to this invention was tested in an oxidation test similar to that described previously, except that the test was conducted for 72 hours, and the metals present were steel, copper, silver, and magnesium (5.5 squ. cm. in area). The metals were all pre-weighed to determine loss through corrosion. The kinematic viscosity of the fluids was measured at F. before and after the test to determine percent change.

The composition consisted of a reaction product of 324 grams of the hydrocracked stock of the above example, 324 grams of the above pentaerythritol ester, and 12.8 grams of dioctyldiphenylamine, all heated in the presence of 58.4 grams of di-tertiary-butyl peroxide. The product was refined in the described manner of Example 1.

The results of oxidation test are compared with a typical ester lubricant containing 2% by weight of antioxidants and which conforms to MIL Specification L 7808F. The comparison values are in parentheses.

Percent change in kinematic viscosity 166 (176) Visual sludge Nil (Nil) Metal corrosion, mg./cm.

Silver 0.0 (0.0) Copper -O.1 (-0.l) Steel 0.0 (0.0) Magnesium 0.1 (50) The compositions of this invention were tested in a weathering test using the Weather-Ometer equivalent described in ASTM D 529. The arc lamp used in this test is a 6000 watt xenon arc lamp. The sample to be tested is rotated around the lamp; the spray cycle was omitted. This test therefore indicates the stability of the composition to ultra-violet radiation. The test Was stopped in each case when sludge formation became visible to the operator, indicating failure.

The untreated hydrocracked oil failed in less than 10 hours. The sludge content was very high. The products of Examples 1 through 7 did not fail, and the tests were discontinued after 430 hours without any sludge formation.

The description and specific embodiment presented herein do not represent limitations of this invention, but are only illustrations thereof. Having described my invention, I claim:

1. The reaction product obtained by heating at a temperature of from about 100 C. to about 200 C. a hydrocracked mineral oil with a synthetic hydrocarbon fluid selected from the group consisting of olefins having from 5 to 15 carbon atoms, the dimers, trimers and tetramers derived from such olefins and the hydrogenated derivatives of such polymers, in the presence of from 1 to about 25% by weight of said hydrocracked mineral oil of an organic peroxide, the synthetic hydrocarbon being present to the extent of from 1% to about 75% by weight of the total composition.

2. The product of claim 1 wherein the hydrocracked oil is derived from an oil selected from the group consisting of a heavy distillate mineral oil boiling at a temperature of at least 650 F. and a vacuum still residue.

3. The product of claim 1 wherein the peroxide has the structure RO--OR' wherein R and R are each selected from the group consisting of hydrogen, alkyl, aralkyl, aryl, alkaryl and acyl, having from 1 to 20 carbon atoms, at least one of which is an organic radical.

4. The product of claim 3 wherein R and R are alkyl radicals having 1 to 10 carbon atoms.

5. The product of claim 4 wherein R and R are tertiary alkyl radicals.

6. The product of claim 5 wherein R and R are tertiary butyl.

7. The product of claim 1 wherein the polymer is a hydrogenated polymer of decene.

References Cited UNITED STATES PATENTS DANIEL E. WYMAN, Primary Examiner W. J. SHINE, Assistant Examiner US. Cl. X.R. 

